correspondence
kɒrɪˈspɒnd(ə)ns
noun
a close similarity, connection, or equivalence.
there is a simple correspondence between the distance of a focused object from the eye and the size of its image on the retina
correlation,similarity,resemblance,comparability,compatibility,agreement,consistency,congruity,conformity,uniformity,harmony,affinity,accordance,accord,concurrence,coincidence,association,relationship,connection,interaction